Confirmed: No drone when cruising and no helicopter sound from AFM/DFM. Recorded using Samsung S23 phone mic from driver's seat.
Parts:
K&N: 57-3108 ($200) and re-used OEM air filter
Corsa: CT30CTR ($365)
Labor:
Intake: 40 minutes - replace resonator (self)
Muffler: 45 minutes - cut and weld ($100)
After taxes, the total price was under $700.
My truck had 23k miles at the time, so I replaced the engine air filter (3x 8mm screws to remove the top of the air box) and cabin filter with OEM filters.